Indicator illumination



3 Sheets-Sheet 1 INVENTOR Y Paul. KQL-LSMBN P. KoLLMAN INbIAToR ILLUMINATION originai Filed lApril 5, 1934 v t C m f ATTORNEY P. KoLLsMAN Sept. l2, 1939.

INDICATOR ILLUMINATION Original Filed April 5, 1934 3 Sheets-Sheet 5 INVENTOR PHUL KOLLSMHN BY ATTORNEY v atentecl Sept. 12, 1939 UNlTED. STATES PATENT OFFICE INDTCA'ron mLUMrNA'rroN Paul Kollsman, New York, N. Y.

Application April 5, 1934, Serial No. 719,11'

Renewed December 9, 1936 24 Claims.. (Cl. 24o-2.1)

This invention relates to iuummauonof mstrument dials.

The object of the invention is to illuminate aA dial emclently, uniformlyand without causing light rays to reach the eyes of the observer ex- In carrying out the object of the invention, it is proposed to mount a source of light, preferably in. the form of a miniature incandescent bulb, directly upon theglass frontof the instrument and to arrange for substantially uniform j distribution radially outwardly from the lamp bulb to the dial in the rear thereof. A further object of the invention -is to permit, where desired, the hermetical sealing of the instrument case by, means of the transparent front despite thefact that it carries a central bulb `socket. A still further object of the invention is to provide for the automatic establishment of an electrical connection between the transparent front carrying the bulb socket and electrical connectors mounted on the casing. A further object of the invention 4is to generate the light for illuminating the dial interiorly of its transparent front and in a locality to prevent direct rays from the bulb passing outwardly through the transparent front.

Further objects and advantages of the invention will be apparent from the following de scription of an illustrative embodiment and will bev pointed out in the following claims. claims are directed to the illustrative embodiment for purposes of explanation and not limital tion. i

' In the drawings, Fig. 1 is a front view of an air speed indicator mounted on an instrument panel and provided with my means for illumination; Fig. 2 is a vertical cross-section, with parts broken away and parts shown in elevation, of an air speed indicator fitted with my invention; Fig.

43 is a distorted, enlarged diagrammatic perspective with parts broken away offa transparent front formed in accordance with my invention;- Fig. 4 is a fractional rear elevation showing the The Although I have shown my invention embodied in an air speed indicator, it is, of course, to be understood that it is applicable to all instruments having scales on dials requiring artificial illumination. In the drawings, the air speed indicator A comprises a casing I adapted to be mounted in an instrument panel 2 as by screws 3 in any wellknown manner, or in accordance with the inven- -tion set forth in my co-pending application.

Many instruments such as altimeters and air speed indicators require hermetical sealing of the casing I. This sealing is completed by a transparent front B usually in Ithe form of a glass disk which may` seat upon a rubber gasket 4 mounted on a ring-shaped ledgeI 5, the glass front beingpressed home in any suitable way as by a split ring 6. This glass front B is opposite a disk-shaped dial 1 which may have any usual or desired scale, such as the scale 8 which in the present instance indicates miles per hour in cooperation with the concentrically rotatable pointer 9, the pointer being shown in-zero position.

objectively, I mount a source of light, as for example, the incandescible filament I0, interiorly of the transparent front B and centrally thereof and supported thereby. I preferably mount said source of light absolutely coaxial with the pointer 9 and the scale indicia, and, of courge, with the disk-shaped dial 1 when uniform illumination over the entire dial is desired, as shown in Figs. 1 and 2, and mount said source of light excentrically with respect to the pointer when emphasis is to be given to certain parts of the scale, lor to avoid interference by the light with the visibility Jof'the pointer or dial parts, as shown in Fig. 3.

To cooperate in' this mounting I prefer a plug and socket construction C, one part II. of which is substantially in the form of a nipple hermetically sealed into a perforation I2 of the transparent front B. The other part is substantially a plug formation I3. A channel I4 is radially positioned and is preferably cut across the inner face ofthe transparent front B which may be of glass as is usual for instrument fronts, or of any suitable transparent material. The fine connecting wires I5 and I6 supplying electrical current to the filament III, are imbedded and cemented in this channel I l, the inner and outer ends of which are appropriately connected to the electrical contacts presently to be described. At the periphery of the front-B a't the outer end of the channel Il, I preferably form a notch I8 to accommodate .the turned-over ends I9 and 20 of the lead wires' -I5 and I6, which ends may be soldered to conf tact plates 2| and 22. I prefer that this entire peripheral construction be finished off flush with the periphery 23 of the front B and that the notch I8 be filled with cement 24 to seat the contacts 2| and 22 holding the wires firmly in place. The cement is shown also extending into channel I4 to hold the wires.

In the rim of the casing I, I seat a pair of terminal thimbles 3| and 32 which may be soldered to the ends of lead-in wires 33 and 34.

' Each thimble is shown tted with a conical spring connector, such as 35 and 36, which expands substantially radially inwardly automatically to contact with the connector plates 2| and 22. By this construction I do not in any way interfere with the sealing gasket 4 of the casing I, or its function to seal the instrument. By positioning the connectors 35 and 36 in a vertically, upward position symmetrically straddling the zero indication of the dial, assistance in assembling my combined transparent front is effected. As a matter of fact, the channel I4 imbedding the fine lead-in wires I5 and I6, functions as a zero line when the instrument is viewed from the front, although this zero line is actually very faint. In assembling my transparent front, all that is' necessary is to insert the part of th rim bearing the plates 2| and 22 first so asto press against the springs 35 and 36. The tting`of the transparent front and its locking by the split ring 6, is thereafter the same as for the transparent fronts heretofore employed. The terminal wires 33 and 34 may be imbedded in and cemented in channel" cut or moulded in the casing I and terminating in a pair of suitable connectors 4| and 42. for connection with power lines which may be two simple wires extending from a dry battery.

The socket has a ledge seating the sealed in Bakelite gasket 46 and is provided internally with screw threads 41. A flange 48 of reduced diameter, providing the shoulder 49, seats in and is cemented in the perforation I2 in the glass front B. A connector 50 in the form of a flanged metal sleeve is insulated from the nipple by an insulating ring 5|. The end's of the wires I5 and I6 are connected respectively to the metal nipple I, as by solder, and to the connector 50 in a similar manner. The connector 5U preferably has one or more inwardly resilient fingers 52. Cooperating with the socket structure is a plug' mount for the incandescible bulb 55. A hollow plug or cap has external screw `threads 6| complementary to the screw threads 41 in the socket. One bulb lead4 62 is soldered to the cap 63 and the other lead 64 is soldered to a cylindrical sleeve 65. mounted axially within the plug 60 by the anged insulating sleeve 66; an insulating cement lling 61 seals the parts together. I preferably paint a cap 10 on the inner end of the bulb 55 so that light emergence is limited to the area designated by 1|. A rubber gasket 12 may also be provided to seat upon gasket 45 and complete a hermetical enclosure for the perforation.

Surrounding and preferably coamal with the dial 1A are one or more mirrored `rings 15 and 16. Fig. 2 shows a preferred arrangement. The

source of light 0 is actually farther inward than the inner face 11 of the glass front B, but the angle of incidence of the rays'therefrom upon this inner surfacel is so large that total reflection inward takes place, these inward reflections illuminating the face of the dial which is preferably blackened ythrourzghcut its entire face except for States Letters Patent is:

-ported by said transparent front in said central the indicia which may be white. To intensify the illumination in the periphery of the disk where the scale occurs, some of the rays extending radially along the face of the dial strike the mirrored surfaces 15 and 16 and are reflected inwardly and rearwardly upon the peripheral portions oi' the dial to intensify the illumination where it is needed. The cap 1li and the plug and socket construction |I'-|3 prevent emergence in an axial direction either inwardly or outwardly of all rays.

In appearance, as shown particularly in Fig. 1, although'I have provided for substantially uniform'illumination of the entire dial, the illuminating structure apparently is a part of the indicator mechanism, the plug and socket' perhaps indicating a central knob on the pointer and the channel I4 suggesting a deliberate zero line.

What I claim and desire to secure by United 1. A new article of manufacture; a transparent front for indicators capable of .completing a. hermetical enclosure comprising a glassdisk provided with a central perforation; a bulb socket capable of being closed from the exterior hermetically'sealed in said perforation; terminal connectors at the periphery of said disk; and lead-in I wires extending radially from said socket to lsaid terminal connectors.

2. A transparent bulb mounting front for in- .s dicators having a pair of electric terminals positioned on its periphery 'with their surfaces substantially flush with the rim of said front.

3. In combination, an indicator casing providing' a seat for a transparent front; a plurality of resilient electrical connectors directed inwardly at the locality of said seat; a transparent front having a lamp socket at its center and being provided with a radial channel; conducting leads imbedded in said charme] and having terminal parts at the outer extremity of said channel for cooperation with said resilient electrical connectors.

4. In combination a transparent front for indicators in the form of a glass disk; a bulb socket mounted centrally on said' disk: said disk having a radial channel and a pair of lead-in wires mounted in said channel; an indicator casing having anindicator dial reading from zero upward; terminal connectors for said ,lead-in wires in Vposition to connect therewith when said radial channel corresponds to the zero indication on said dial.'

5.-In combination in an instrument adapted to present an easily visible indication, a casing; an indicating dial mounted in said casing; a transparent front supported by said casing and opposite said dial h'aving a central perforation; an electric' lamp bulb removably centrally supperforation with provisions for hermetically sealing said perforation; said provisions including a female threaded socket sealed to said fro'nt and a threaded plug-mount' for said bulb, both said bulb and said plug being mountable and demountable from the outsid'e of said front without removing said front from said casing; and electricall leads extending from the locality oi.' 4said bulb outwardly to the rim of said transparent front; and means for sealing said casing to said transparent front.

6. In combination for illuminating the indicating parts of an indicator comprising a casing; operating mechanism in said easing; movable indicating parts operated by said mechanism; an

glass window adjacent said dial, electrical conductors imbedded in said window extending to said socket, and forming a reference line in cooperative relationship with said dial, an electric .bulb and base mechanism, the bulb and base means around said dial, the angle at the reflecting therethrough connected form said reference line.

ing surface ofsaid cone to rays oflight from said light source being approximately whereby a portion ofthe light from said illuminant falls directly upon said dial, another portion falls upon said conical reflecting means and is reflected to said dial, and a third portion is reflected from said window to said reflecting means and thence to said dial, and means for restricting the channel of light passage to limitthe light flux substantially to the graduations of said scale comprising an opaque capvupon the end of the said bulb and an opaque annular portion of' said socket cooperating therewith to limit the light paths to an annular outlet opening. substantially all emitted light falling either directly or after rd'fllection upon -the graduated portion of said 15. In an indicating instrument, a glass window having an opening therethrough, a slot extending from said opening, an electrical conductor in said slot extending to said opening and forming a reference line for said'instrument, a socket supported in said opening, and electric lamp passto said leads which 16. An article of manufacture comprising a glass window member having an opening therethrough; a socket supported'ln said opening, the said socket having a 'passage from end to end thereof for a passingtherethrough of an electric lamp member; electrical conductors embedded in said window leading from said socket to the edge of said glass window.

17. An article Iof.' manufacture comprising a 'window member for' use inV an instrument case, a

socket member airtightly supported lby said window, said socket member having a passageway therethrough yfrom end to end and providing a sealing face; ai lamp'and 'base'member insertable through said socket and securabletherei'n with the illuminant portion of said lamp projectingfrom said socket on the side of said window remote from the side of entrance said base being formed as to flt air-tightly against said sealing face; and conductor members mounted on said window leading from said socket to the edge of transparent portion and an aperture opening towards the front of said casing; first contact elements in said aperture completing said aperture to form a lamp socket; a circular dial visible through said transparent portion; a ring-shaped reflecting member arranged substantially parallel with and adjacent to the rim portion of said dial to reflect light unto said dial; a lamp having second contact elements complementary to said first elements and a glass bulb of smaller diamjeter than said aperture, said lamp being insertable from thefront of said casing into said socket into a position to emit light onto said reflecting member.

20. In an instrument illuminating system the combination of an instrument casing having a transparent window and a central aperture therein opening towards the front of saidcasing; first cont'act elements in said aperture completing said aperture to form a lamp socket;4 a circular dial visible through said transparent portion; a ring-shaped reflecting member arranged substantially parallel with and adjacent to the riml portion of said -dial to reflect light unt'o said dial; a lamp' having second contact elements complementary to said first elements and a glass bulb ofr smaller diameter than said aperture, said bulb havingian opaque tip portion and being insertable from the front of said casing into said socket into a position to emit light onto said reflecting member.

21. In an instrument illuminating system the combination of an instrument casing having a transparent portion and an aperture opening t0- Wards the front of said casing; first contact elements in said aperture completing said aperture to form a la'mp socket; a circular dial visible through said transparent portion; a ring-shaped reflecting member arranged substantially parallel with and adjacent the rim portion of said dial to reflect light unto said dial; a lamp having a base providing second contact elements complementary to said flrst elements and a glassibulb of a width not exceeding the width of said base, said lamp being insertable from the front of said casing into said socket into a position to emit light onto said reflecting member.

22. An indicating instrument comprising, in combination, an airtight instrument casing having a transparent portion and an internally threaded aperture opening towardsv the front of said casing; indicating meansvisible through said transparent portion; first contact elements completing said aperture to forma lamp socket; a lamp including a glass bulb of smaller diameter than said aperture, and an 'externally screwthreaded base providing second lcontact elements complementary to said first contact elements and a flnger'grip portion, said lamp being insertable from the front of said casing into said aperture into a position to emit light unto said indicating means; and sealing provisions between said aperture and said lamp socket effecting an airtight closure between said base and casing. 23.) An indicating instrument comprising, i

"combination, an airtight instrument casing having a transparent portion and an aperture open- I ingtowards the front of said casing, said aperture being formed to provide a sealing face; indicating means visible through saidtransparent portion; rst contact elements completing said aperture to form a lamp socket; a lamp including a glass bulb of smaller diameter than said aperture and a lamp base having a finger grip portion and provisions for engaging said aperture, said baseJ having second contact elements complementary vto said first contact elements and being formed arranca as to iit air-tightly against said sealing i'ace upon being inserted into said aperture into a position to emit iight onto said indicating means.

24. An indicating instrument comprising, in combination, an airtight and substantially cylindrical instrument casing; a transparent circular window airtightly supported by said casing, said window having a central aperture opening to- `wards the front of said casing, said aperture being formed to provide a sealing face; indicating means including a circular dial visible through said window; iirst contact elements completing said aperture to form a lamp socket; a lamp including a glass bulb of smaller diameter than said a'pei'ture and a lamp beschaving a finger grip portion and provisions for engaging said aperture, said base having second contact elements complementary to said nrst contact elements and being formed as to fit 4airtightly against said sealing face upon being inserted into said aperture into a position to emit light onto said indicating means.

wPAUL KOLLSMAN. 

